Electric switch



Filed July 1 4 1939 Inventor: Franz peterrnichl,

by His Attorney.

Feb. 25, 1941.

\ 2 Au I s. W r n NM 3 ER Em 6M n a 3 V 4 villi/4 76m! rill/ll!!! H 6 8 r 7 M A I I l I 1 I I I I l i l I I I M fl A J v 7 [1|llllllllllllllp l wlnlllll H I 4r I M 3 n 0 0 m 2 Patented F b. 25, 1941 UNITED STATES PATENT OFFICE ELECTRIC SWITCH Application July 1, 1939, Serial No. 282,541 In Germany September 1, 1938 6 Claims.

The present invention relates to electric switches, and particularly to electric switches of the type in which afluid blast is-employed for extinguishing the arc drawn between the con- 6 tacts when the switch is opened.

It is an object of this invention to provide a switch of the above type which is simple, compact and inexpensive to manufacture and, at the same time, rugged and efficient in operation.

10 It is another object of this invention to provide a switch of the above type which is free from ,flashovers, either between the parts of an individual switch or between the parts of adjacent switches when they are mounted in close prox- 15 imity in a multi-phase installation.

In accordance with an important feature of the present invention the operative parts of the switch are enclosed in a single elongated body of insulating material which forms a support for 20 the relatively movable contacts and also provides chambers for expanding and cooling the exhaust gases before they are discharged into the surrounding atmosphere. The construction also provides for directing the exhaust in such a way that the likelihood of a flashover is reduced to a minimum.

Further objects and advantages of the present invention will become apparent as the following description proceeds, reference being had to the 30 single figure of the accompanying drawing which shows an elevational view, partly in section, of a switch embodying the invention.

Referring to the drawing, a switch embodying my invention includes an elongated body I of 3-) suitable insulating material which in the preferred embodiment illustrated is in the form of a hollow cylinder. The body is supported from a vertical wall by a base 2 and a supporting insulator 3. Secured in the lower end of the body l 40 is a supporting spider 4 including a plurality of radially extending arms 5 which form a support for a movable contact guide 6 extending axially of the switch body I. A hollow movable contact 1 is positioned in the guide member 6 and ar- 45 ranged to be reciprocated by a pivoted arm 8 which extends through an opening in the side wall of the switch body and is connected to the movable contact by means of a pin and slot connection. Any suitable arrangement (not shown) 50 may be employed for actuating the arm 8 in accordance with the circuit conditions to be controlled.

An apertured transverse partition 9 of insulating material is provided in the switch body to slightly above the upper end 01. the movable contact when it is in its open circuit position and divides the body into two compartments or chambers I0 and II. The stationary contact [2 is mounted in the upper compartment lflin a hollow reentrant portion I3 of the body I. The reentrant portion i3 may be in the form of a separate tube of insulating material concentrically supported from the walls of the switch body by a spider, or it may be molded integrally therewith.

In either case the construction is such as to define 10 passages between the inner wall of the switch body and the outer wall of the reentrant portion. These passages form a part of the exhaust chamber Ill. The fixed contact I2 is positioned above the lower end of the reentrant tube and is preferably provided with a filler rod M of a gas-emitting fiber or similar material which lies within the movable contact rod in the closed circuit position of the switch. The lower end of the reentrant tube and the apertured partition member 9 are provided with aligned cylinders l5 and I6 which are provided with cylindrical liners ll of gas-emitting material. The cylinders I5 and I6 are dimensioned to provide a space between their adjacent ends which communicates with the upper chamber In formed between the inner wall of the switch body and the reentrant portion l3. This construction forms, in effect, a two-part arc passage having communication intermediate the ends thereof with the exhaust chamber 1 0. This exhaust chamber is preferably provided near its outer end with a muffler and cooler l8 of any suitable construction.

When the switch described above is moved to closed circuit position the movable contact passes through the aligned passages formed by the cylindrical liners I1 and engages the stationary contact 12. When the breaker is moved to open circuit position under load conditions an arc is drawn between the stationary contact and the tip of the movable contact I. As the movable contact is withdrawn the arc acts upon the lining of gas-emitting material of the upper cylinder I5 and the filler pencil to produce a considerable pressure of arc-extinguishing gas. As the movable contact leaves the upper cylinder these gases escape into the exhaust chamber H) where they expand and cool before leaving the'outer end through the mufller I8. If the current is large, the pressure generated by the action of the arc in the first cylinder IE will be sufficient to extinguish the are by the time the movable contact has been withdrawn into the lower tube l6. In some cases, for example, when the load current is light the gas generated in the first tube will be insuflicient to extinguish the arc and the action described above is repeated in the lower tube I5. I! desired, the movable contact may be provided with damping means for slowing it up as it leaves the upper tube so as to produce a slight pause and increase the effectiveness of the gas blast into the upper chamber II). If the arc is not extinguished in the upper chamber, gas emitted from the liner of the lower tube IE will pass into the chamber I I ,tormed on the lower side of the transverse partition where it will cool before it is discharged into the surrounding atmosphere through the openings between the arms 5 of the supporting spider I. If desired, a muiiier similar to that employed at the outer end of the exhaust chamber III may be used to further cool the gases ex hausted from chamber I I.

The circuit connection with the stationary contact I2 is made by conductor I9 which is preterably brought out through the side of the switch body and passes through a portion of the exhaust chamber III. In order to prevent any arcing-over between the movable contact and this conductor due to the presence of the hot ionized gas in the chamber III, the conductor is provided with an insulating sleeve 20. With this construction the conductor I9 is located remote from the points at which the exhaust gases are emitted from the switch so that the likelihood of an external flashover is reduced to a minimum. As an alternative construction the conductor I9 may extend axially from the reentrant tube I3 in which case it is insulated for a suiliclent distance above the switch body to prevent the occurrence of a flash- OVEI.

From the foregoing description it is apparent that the present construction is simple and provides a unitary housing which not only supports the fixed and movable contacts but which is arranged to form exhaust chambers for expanding and cooling the hot ionized gases and directs them in such a way as to diminish the likelihood of fiashovers between the parts of the individual switch or the switches of adjacent phases. The construction also forms two expansion chambers for the gases exhausting from the arc passages. The upper chamber which houses the stationary contact is arranged to receive the gases emitted when a high current are is extinguished. These gases are hotter and more likely to cause flashovcr than the gases exhausted from a low current arc. In accordance with the present construction these gases are exhausted away from all of the conducting parts of the switch including the stationary contact and the circuit connection therewith. The lower part 01 the switch body forms an expansion chamber for the less highly heated gases which are exhausted when the low current are is extinguished. This part oi the body also houses the movable contact structure and prevents the gases from being exhausted in the atmcsphere surrounding the movable contact structures of adjacent switches until after it has been cooled sufficiently to diminish the possibility 01' a iiashover between switches of adjacent phases. The use of two exhaust chambers, one of which houses the stationary contact and the other the movable contact results in an extremely compact, yet reliable switch.

While I have shown and described a particular embodiment of my invention, it will be apparent to those skilled in the art that many modifications might be made, and I intend in the following claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric switch of the fluid blast type comprising an elongated hollow body of insulating material, a hollow insulating support mounted in said body, a fixed contact mounted in said support, a movable contact mounted in and supposted from said body in longitudinally spaced relation to said support and movable into and out of engagement with said fixed contact, said hollow support having portions thereof spaced from the inner walls oi said body to form an exhaust chamber opening away from the direction of opening movement of said movable contact.

2. An electric switch of the fluid blast type comprising an elongated hollow body of insulating material having an apertured transverse partition therein dividing said body into two chambers each communicating independently with the exterior of said body, a stationary contact mounted in one of said chambers, a movable contact mounted in the other of said chambers, means defining an arc passage having communication at spaced points along its length with a different one of said chambers, and means for supplying arcextinguishing fluid to said passage.

3. An electric switch of the gas blast type comprising relatively fixed and movable contacts, means defining an arc passage in the path of movement of one of said contacts, means for supplying are-ex tinguishing gas to said passage, means defining a pair of exhaust chambers, one of said chambers having communication with said are passage at an intermediate point along its length and the other of said exhaust chambers having communication with an end of said are passage the communication between said are passage and said other chamber being restricted during separating movement of said contacts until after communication between said one chamber and the intermediate point of said are passage is established so that gas exhausted upon the interruption of heavy current arcs is exhausted into said one chamber and the gas exhausted upon interruption of light current arcs is exhausted into said other chamber.

4. An electric switch of the fluid blast type comprising an elongated body of insulating material having an apertured partition therein dividing said body into two chambers each communicating independently with the exterior of said body, said body having a hollow insulating support in one chamber, a fixed contact mounted in said hollow support in spaced relation to the inner end thereof, the inner end of said support and said apertured partition being shaped to provide a two-part arc passage, means for supplying fluid to said passage, a movable contact mounted in the other of said chambers and movable through said arc passage into and out of engagement with said fixed contact, said contact being effective to close the aperture in said partition during a portion of the opening movement thereof so that the fluid exhausted from the arc passage of said support is exhausted into said one chamber.

5. An electric switch of the gas blast type comprising an elongated body of insulating material having an apertured partition therein dividing said body into two chambers each communicating independently with the exterior of said body, said body having a reentrant portion in one chamber, a fixed contact mounted in said reentrant portion in spaced relation to the inner end thereof, the

inner end of said reentrant portion and said ap- I ertured partition being shaped to provide a twopart are passage having a lining of gas-emitting material, a movable contact mounted in the other of said chambers and movable through said are passage into and out of engagement with said fixed contact, said contact being effective to close the aperture in said partition during a portion of the opening movement of said switch whereby the gas generated in the arc passage of said reentrant portion is exhausted into said one chamber.

6. An electric switch of the gas blast type comprising an elongated hollow cylinder of insulating material, a hollow support of insulating material mounted in said cylinder and concentric therewith, a fixed contact mounted in said support in spaced relation to the inner end thereof, a movable contact separable from said fixed contact to draw an arc, means defining an arc-confining passage in the path of separating movement of said movable contact, means for supplying arc-extinguishing gas to said arc-confining passage, said cylinder forming an expansion chamber for the reception of gas exhausted from said arc-confining passage, said chamber opening away from the direction of separating movement of said movable contact through a passage defined by an inner wall of said cylinder and an outer wall of said hollow support.

FRANZ PETERMICHL. 

